An effective host response to infection or tissue damage requires focal accumulation of leukocytes. Leukocyte adhesion to the vessel wall, a key step in this process, depends on the ordered expression of specific endothelial cell surface molecules. The endothelial molecules that support adhesion include selectins that recognize leukocyte cell surface glycoconjugates as well as members of the immunoglobulin superfamily that interact with leukocyte integrins. Although inflammation can occur with minimal damage to the vessel wall and surrounding tissues, control mechanisms sometimes appear to fail, and the inflammatory response itself becomes a significant clinical problem. In this review, we discuss endothelial-leukocyte adhesion molecules with particular emphasis on their expression and function in human disease. Pathophysiological processes presented include atherosclerosis, ischemia-reperfusion injury, acute lung injury, rheumatoid arthritis, and graft rejection. A more detailed description of the discovery and characterization of the key molecules appears in the antecedent article entitled “Endothelial-Leukocyte Adhesion Molecules” .